1. Technical Field
The present invention relates to an illumination device using a light source unit having a point like light source and a light guide plate, a method of assembling the illumination device, and a liquid crystal display device equipped with the illumination device.
2. Related Art
A liquid crystal display device is not a self-light emitting element that emits light by itself but a passive element that displays an image by some sort of light from outside. Accordingly, an illumination device such as a front light, a back light, or the like is used in the liquid crystal display device.
There are two main types of the illumination device of the liquid crystal display device, a direct type capable of providing high luminance, high efficiency, and upsizing, and an edge light (side light) type for compact size, thin model, and low power consumption.
In the direct type, lamps are aligned on a back surface of a liquid crystal panel and direct light is used to form a surface light source that provides high luminance and high efficiency. However, there is a disadvantage that, for example, power consumption is large.
On the other hand, in the edge light type, not less than one light source is disposed on a side surface of a light guide plate (light guide) to form a surface like light source by defusing/scattering light in the light guide plate. Herewith, thinning and reduction of power consumption are provided.
The life of the liquid crystal display device approximately depends on the life of the light source, so that there is an advantage that the liquid crystal display device can be semi permanently used if a maintenance for exchanging a damaged light source for a new one is performed.
As such an edge light type liquid crystal display device, it is known that a light source is integrated with a light source holding body and the light source holding body is made to be detachable from a housing of the illumination device by a sliding mechanism, and an exchange operation of the light source is performed by separating the light source with the light source holding body from the housing (for example, see Japanese Patent No. 2823993).
Incidentally, a simplified exchange structure is established as for a CFL (cathode fluorescent lamp) that is a general light source. However, as for an LED unit using an LED (light emitting diode) as a light source, there is a fear of occurrence of cracking of the solder fixing an LED chip with a printed substrate or unsticking of the LED chip from the printed substrate due to contact of the LED chip and the light guide plate when slide exchange is performed as the CFL.